Synthesis of anti-estrogenic and other therapeutic steroids from 21-hydroxy-19-norpregna-4-en-3-one

ABSTRACT

Syntheses of steroids such as 3-hydroxy-7α-methyl-21-[2′-methoxy-4′-(diethylaminomethyl)-phenoxy]-19-norpregna-1,3,5(10)triene citrate (“SR 16234”) and analogs thereof are provided, wherein 21-hydroxy-19-norpregna-4-en-3-one serves as a starting material or intermediate. The latter compound may be readily prepared from estrone-3-methyl ether. Certain intermediates in these syntheses also have value as therapeutic agents, for example in the treatment of prostate disorders such as prostatic cancer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.09/780,990, filed Feb. 9, 2001, now U.S. Pat. No. 6,784,170, whichclaims priority under 35 U.S.C. §119(e)(1) to provisional U.S. PatentApplication Ser. No. 60/181,738, filed Feb. 11, 2000, both incorporatedherein in their entireties.

TECHNICAL FIELD

This invention relates generally to the chemical synthesis of steroids,and more particularly relates to the synthesis of anti-estrogenic andother therapeutic steroids such as3-hydroxy-7α-methyl-21-[2′-methoxy-4′-(diethylaminomethyl)-phenoxy]-19-norpregna-1,3,5(10)trienecitrate (“SR 16234”) and analogs thereof. The invention additionallyrelates to starting materials and intermediates useful in conjunctionwith the novel synthesis.

BACKGROUND

Breast cancer is one of the most prevalent types of cancer, andepidemiological and clinical studies have shown that approximatelytwo-thirds of breast tumors are estrogen-dependent. This means thatestrogens are required for the growth of such breast tumors in bothpremenopausal and postmenopausal patients. In postmenopausal women, inwhom breast cancer most commonly occurs, breast tumor concentrations ofestrone and estradiol are considerably higher than blood estrogenlevels. Although retention of estrogens in breast tumors byhigh-affinity binding proteins contributes to the level of estrogens intumors, estrogen concentrations in the breast are higher than plasmalevels in breast cancer patients regardless of whether their tumors areestrogen receptor-positive (ER+) or estrogen receptor-negative (ER−). Insitu formation of estrogen from estrogen biosynthetic precursors withintumors is now known to make a major contribution to the estrogen contentof breast tumors.

Numerous other estrogen-dependent conditions, disorders, and diseaseshave been identified as well, including, but not limited to, ovarian,uterine and pancreatic cancers, galactorrhea, McCune-Albright syndrome,benign breast disease, and endometriosis.

Estrogenic effects are mediated by specific receptors located in thenucleus of estrogen-responsive cells. The receptor contains ahormone-binding domain for binding estrogen, transcription activatingdomains, and a DNA binding domain. The binding of the receptor-hormonecomplex to estrogen response elements (ERE's) in the DNA of target genesis necessary for regulating gene transcription.

Drugs that competitively block estrogen binding to its receptor, termedanti-estrogens, are capable of inhibiting the stimulatory effects of thehormone on cell proliferation and are therefore useful in the clinicaltreatment of breast cancer. Clinically, estrogen receptor-positivetumors respond with a higher frequency to anti-estrogens than do tumorslacking a significant level of receptors.

Anti-estrogenic drugs fall into two chemical classes: nonsteroidal andsteroidal. The nonsteroidal anti-estrogen tamoxifen (Nolvadex

) has been used as an adjunctive treatment for breast cancer followingchemotherapy or radiation therapy. However, tamoxifen itself exhibitsestrogenic activity in reproductive tissue, resulting in an increasedrisk of endometrial cancer and possible recurrence of breast cancerafter long-term therapy. Furthermore, tamoxifen behaves only as apartial agonist in the uterus.

To date, little work has been done in the development of selectivecompetitive antagonists of estrogen. Several steroidal anti-estrogenshave been synthesized which lack estrogenic activity. Included amongthese are ICI 164,384, ICI 182,780 and RU 58668. See, e.g.: Wakeling etal. J. Steroid Biochem. 31:645-653 (1988), which pertains to ICI164,384; Wakeling et al., Cancer Res. 51:3867-3873 (1991), and Wakelinget al., J. Steroid Biochem. Molec. Biol. 37:771-774 (1990), whichpertain to ICI 182,780; and Van de Velde et al., Ann. N.Y. Acad. Sci.761:164-175 (1995), Van de Velde et al., Pathol. Biol. 42:30 (1994), andNique et al., Drugs Future 20:362-366 (1995), which relate to RU 58668.Unfortunately, these drugs are not orally active and must beadministered in high doses intramuscularly. Furthermore, the manufactureof these drugs is laborious, requiring a complicated, 14-16 stepsynthesis with very low overall yields. Potent steroidal anti-estrogensthat are orally active have not yet been developed or commercialized,although the nonsteroidal mixed agonist/antagonist “raloxifene” iscurrently available.

Accordingly, steroidal active agents have recently been developed thatare extremely effective anti-estrogenic agents, i.e., are potentantagonists of estrogen in breast and/or uterine tissue. The activeagents are described in co-pending, commonly assigned U.S. patentapplication Ser. No. 08/998,877, filed Dec. 24, 1997, now U.S. Pat. No.6,054,446, and U.S patent application Ser. No. 09/220,408, filed Dec.23, 1998, (now U.S. Pat. No. 6,281,205) as well as in PCT PublicationNo. WO 99/33859, published Jul. 8, 1999. These active agents represent asignificant advance in the art, particularly in the treatment of breastcancer and other diseases and conditions that are potentiated by thepresence of estrogens. A number of those active agents have also beenfound to display tissue-selective pharmacology and are thus useful astissue-selective estrogen agonists/antagonists, also termed “SelectiveEstrogen Receptor Modulators” or “SERMs.” SERMs produce beneficialestrogen-like effects in some respects, notably on bone and lipidmetabolism, while nevertheless acting as estrogen antagonists in thebreast and/or uterus. The SERM profile may be distinguished from that ofa pure estrogen such as 17β-estradiol, which behaves as an estrogenagonist in all tissues, and from that of a pure anti-estrogen, whichexhibits an estrogen antagonist profile in all tissue types.

An exemplary and representative anti-estrogen in the aforementionedgroup is the citrate salt of3-hydroxy-7α-methyl-21-[2′-methoxy-4′-(diethylaminomethyl)-phenoxy]-19-norpregna-1,3,5(10)triene,developed at SRI International (Menlo Park, Calif.) and also referred toherein as “SR 16234.” SR 16234 can be represented as follows:

SR 16234 has been found to have potent antitumor activity withremarkable tissue-selective properties: completeantagonist-antiestrogenic activity in human breast tumor cells; completeanti-uterotrophic antagonist activity in rat and human uterine tissue;agonist-estrogenic activity in the cardiovascular system, as reflectedin lowered low-density lipoprotein (LDL) and increased high-densitylipoprotein (HDL) cholesterol levels in rats; and agonist-estrogenicactivity in the skeletal system, as manifested by maintenance of boneand prevention of bone loss in rats. In addition, SR 16234 has beenestablished to have good oral bioavailability, absorption and half-life,with sufficient uptake to sustain therapeutically effective plasmalevels of the drug.

Currently, SR 16234 is synthesized using a nine-step synthetic procedureas outlined in FIG. 1. While the synthesis is effective and provides theproduct in a reasonable overall yield, it would be desirable to providea simpler, more straightforward synthesis so as to reduce cost(synthesizing SR 16234 using the method of FIG. 1 is quite expensive),to improve overall yield, to avoid use of highly toxic reagents, and toavoid costly and difficult reaction steps such as aromatization withCuCl₂.

SUMMARY OF THE INVENTION

Accordingly, the invention is directed to a new method for synthesizingSR 16234 and substituted analogs thereof, which is simpler, morestraightforward and more cost-effective than previous synthetic methods,avoids the use of highly toxic reagents, and furthermore avoids costlymaterials and difficult reaction steps.

It is another object of the invention to provide such a method thatemploys 21-hydroxy-19-norpregna-4-en-3-one or a substituted analogthereof as a starting material or intermediate.

It is still another object of the invention to provide intermediatecompounds and synthetic steps useful in conjunction with theaforementioned syntheses.

It is still another object of the invention to provide certain of suchintermediate compounds as therapeutic agents, e.g., in the treatment ofprostate disorders such as prostatic cancer.

Additional objects, advantages and novel features of the invention willbe set forth in part in the description which follows, and in part willbecome apparent to those skilled in the art upon examination of thefollowing, or may be learned by practice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a synthetic scheme illustrating a prior method forsynthesizing SR 16234.

FIGS. 2, 3 and 4 are schemes illustrating methods of the invention forsynthesizing SR 16234 from estrone-3-methyl ether (1) via21-hydroxy-19-norpregna-4-en-3-one (3) as an intermediate.

FIGS. 5, 6 and 7 are schemes illustrating alternative methods of theinvention for synthesizing3-hydroxy-7α-methyl-21-[2′-methoxy-4′-(diethylaminomethyl)-phenoxy]-19-norpregna-1,3,5(10)triene(“SR 16233”), the free amine precursor to SR 16234.

FIGS. 8 and 9 are schemes illustrating methods of the invention forsynthesizing SR 16234 from a crude 21-hydroxy-19-norpregna-4-en-3-one(3a).

FIG. 10 is a ¹H NMR spectrum of compound 2, the structure of which isshown in FIGS. 2, 3 and 4 (synthesized as described in Example 1).

FIG. 11 is a ¹H NMR spectrum of compound 3, the structure of which isshown in FIGS. 2, 3 and 4 (synthesized as described in Example 1).

FIG. 12 is a ¹H NMR spectrum of compound 4, the structure of which isshown in FIGS. 2 and 3 (synthesized as described in Example 2).

FIG. 13 is a ¹H NMR spectrum of compound 5, the structure of which isshown in FIGS. 2 and 3 (synthesized as described in Example 2).

FIG. 14 is a ¹H NMR spectrum of compound 6, the structure of which isshown in FIGS. 2 and 3 (synthesized as described in Example 2).

FIG. 15 is a ¹H NMR spectrum of compound SR 16233, the structure ofwhich is shown in FIGS. 2 and 3 (synthesized as described in Example 2).

FIG. 16 is a mass spectrum of compound SR 16233.

FIG. 17 is a ¹H NMR spectrum of compound SR 16234, the structure ofwhich is shown in FIGS. 2 and 3 (synthesized as described in Example 2).

FIG. 18 is a mass spectrum of compound SR 16234.

FIG. 19 is a ¹H NMR spectrum of compound 7, the structure of which isshown in FIGS. 2 and 3 (synthesized as described in Example 3).

FIG. 20 is a ¹H NMR spectrum of compound 11, the structure of which isshown in FIG. 4 (synthesized as described in Example 4).

FIG. 21 is a ¹H NMR spectrum of compound 12, the structure of which isshown in FIG. 4 (synthesized as described in Example 4).

FIG. 22 is a ¹H NMR spectrum of compound 13, the structure of which isshown in FIG. 4 (synthesized as described in Example 4).

FIG. 23 is a graph illustrating the % inhibition versus concentration ofSR 16312 as evaluated in an androgen-independent human prostate cancerassay, described in Example 7.

DETAILED DESCRIPTION OF THE INVENTION

Definitions:

It is to be understood that unless otherwise indicated, this inventionis not limited to specific starting materials, reagents or reactionconditions, as such may vary. It is also to be understood that theterminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting.

It must be noted that, as used in the specification and the appendedclaims, the singular forms “a,” “an,” and “the” include plural referentsunless the context clearly dictates otherwise.

In this specification and in the claims that follow, reference will bemade to a number of terms that shall be defined to have the followingmeanings:

The term “alkyl” as used herein refers to a branched or unbranchedsaturated hydrocarbon group of 1 to 24 carbon atoms, such as methyl,ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, octyl, decyl,tetradecyl, hexadecyl, eicosyl, tetracosyl and the like, as well ascycloalkyl groups such as cyclopentyl, cyclohexyl, and the like. Theterm “lower alkyl” intends an alkyl group of one to six carbon atoms,preferably one to four carbon atoms. The term “cycloalkyl” as usedherein refers to a cyclic hydrocarbon of from 3 to 8 carbon atoms, suchas cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, andcyclooctyl.

The term “alkenyl” as used herein refers to a branched or unbranchedhydrocarbon group of 2 to 24 carbon atoms containing at least one doublebond, such as ethenyl, n-propenyl, isopropenyl, n-butenyl, isobutenyl,octenyl, decenyl, tetradecenyl, hexadecenyl, eicosenyl, tetracosenyl,and the like. Preferred alkenyl groups herein contain 2 to 12 carbonatoms. The term “lower alkenyl” intends an alkenyl group of two to sixcarbon atoms, preferably two to four carbon atoms. The term“cycloalkenyl” intends a cyclic alkenyl group of three to eight,preferably five or six, carbon atoms.

The term “alkynyl” as used herein refers to a branched or unbranchedhydrocarbon group of 2 to 24 carbon atoms containing at least one triplebond, such as ethynyl, n-propynyl, isopropynyl, n-butynyl, isobutynyl,octynyl, decynyl, and the like. Preferred alkynyl groups herein contain2 to 12 carbon atoms. The term “lower alkynyl” intends an alkynyl groupof two to six carbon atoms, preferably two to four carbon atoms.

The term “alkylene” as used herein refers to a difunctional branched orunbranched saturated hydrocarbon group of 1 to 24 carbon atoms, such asmethylene, ethylene, n-propylene, n-butylene, n-hexylene, decylene,tetradecylene, hexadecylene, and the like. The term “lower alkylene”refers to an alkylene group of one to six carbon atoms, preferably oneto four carbon atoms.

The term “alkenylene” as used herein refers to a difunctional branchedor unbranched hydrocarbon group of 2 to 24 carbon atoms containing atleast one double bond, such as ethenylene, n-propenylene, n-butenylene,n-hexenylene, and the like. The term “lower alkenylene” refers to analkylene group of two to six carbon atoms, preferably two to four carbonatoms.

The term “alkoxy” as used herein intends an alkyl group bound through asingle, terminal ether linkage; that is, an “alkoxy” group may bedefined as —O-alkyl where alkyl is as defined above. A “lower alkoxy”group intends an alkoxy group containing one to six, more preferably oneto four, carbon atoms.

The term “acyl” is used in its conventional sense to refer to asubstituent alkyl-C—(O)— wherein alkyl is as defined above. The term“lower acyl” refers to an acyl group wherein the alkyl moiety of thegroup contains one to six, more preferably one to four, carbon atoms.

The term “aryl” as used herein, and unless otherwise specified, refersto an aromatic species containing 1 to 3 aromatic rings, either fused orlinked, and either unsubstituted or substituted with 1 or moresubstituents typically selected from the group consisting of loweralkyl, lower alkoxy, halogen, and the like. Preferred aryl substituentscontain 1 aromatic ring or 2 fused or linked aromatic rings. The term“arylene” refers to a difunctional aromatic species containing 1 to 3aromatic rings substituted with 1 or more substituents as above.Preferred arylene substituents contain 1 aromatic ring (e.g., phenylene)or 2 fused or linked aromatic rings (e.g., biphenylylene).

The term “aralkyl” refers to an aryl group with an alkyl substituent.The term “aralkylene” refers to an arylene group with an alkylsubstituent.

The term “alkaryl” refers to an alkyl group that has an arylsubstituent. The term “alkarylene” refers to an alkylene group that hasan aryl substituent.

The term “heterocyclic” refers to a five- or six-membered monocyclicstructure or to an eight- to eleven-membered bicyclic heterocycle. The“heterocyclic” substituents herein may or may not be aromatic, i.e.,they may be either heteroaryl or heterocycloalkyl. Each heterocycleconsists of carbon atoms and from one to three, typically one or two,heteroatoms selected from the group consisting of nitrogen, oxygen, andsulfur, typically nitrogen and/or oxygen.

The terms “halo” and “halogen” are used in the conventional sense torefer to a chloro, bromo, fluoro, or iodo substituent. The terms“haloalkyl,” “haloalkenyl,” or “haloalkynyl” (or “halogenated alkyl,”“halogenated alkenyl,” or “halogenated alkynyl”) refers to an alkyl,alkenyl, or alkynyl group, respectively, in which at least one of thehydrogen atoms in the group has been replaced with a halogen atom.

The term “hydrocarbyl” is used in its conventional sense to refer to ahydrocarbon group containing carbon and hydrogen, and may be aliphatic,alicyclic, or aromatic, or may contain a combination of aliphatic,alicyclic, and/or aromatic moieties. Aliphatic and alicyclic hydrocarbylmay be saturated or they may contain one or more unsaturated bonds,typically double bonds. The hydrocarbyl substituents herein generallycontain 1 to 24 carbon atoms, more typically 1 to 12 carbon atoms, andmay be substituted with various substituents and functional groups, ormay be modified so as to contain ether, thioether, —NH—, —NR, —C(O)—,—C(O)—O—, and/or other linkages.

“Optional” or “optionally” means that the subsequently describedcircumstance may or may not occur, so that the description includesinstances where the circumstance occurs and instances where it does not.For example, the phrase “optionally substituted” means that anon-hydrogen substituent may or may not be present, and, thus, thedescription includes structures wherein a non-hydrogen substituent ispresent and structures wherein a non-hydrogen substituent is notpresent. Similarly, the phrase an “optionally present” double bond asindicated by a dotted line ----- in the chemical formulae herein meansthat a double bond may or may not be present, and, if absent, a singlebond is indicated.

By “anti-estrogenic” as used herein is meant a compound that tends toinhibit the in situ activity of estrogens such as estradiol, followingadministration to a mammalian individual. Anti-estrogenic activity canbe evaluated in terms of inhibition of estradiol-induced alkalinephosphatase activity in human Ishikawa cells using, for example, theprocedures described in Example 40 of PCT Publication No. WO 99/33859.

The terms “treating” and “treatment” as used herein refer to reductionin severity and/or frequency of symptoms, elimination of symptoms and/orunderlying cause, prevention of the occurrence of symptoms and/or theirunderlying cause, and improvement or remediation of damage. Thus, forexample, a method of “treating” an estrogen-dependent disorder, as theterm is used herein, encompasses both prevention of the disorder in aclinically asymptomatic individual and treatment of the disorder in aclinically symptomatic individual. Similarly, a method of “treating” aprostate disorder, as the term is used herein, encompasses bothprevention of the disorder in a clinically asymptomatic individual andtreatment of the disorder in a clinically symptomatic individual.

By the terms “effective amount” or “pharmaceutically effective amount”of a therapeutic agent are meant a nontoxic but sufficient amount of theagent to provide the desired prophylactic or therapeutic effect. As willbe pointed out below, the exact amount required will vary from subjectto subject, depending on the species, age, and general condition of thesubject, the severity of the condition being treated, and the particularagent and mode of administration, and the like. Thus, it is not possibleto specify an exact “effective amount.” However, an appropriate“effective” amount in any individual case may be determined by one ofordinary skill in the art using only routine experimentation.

By “pharmaceutically acceptable carrier” is meant a material that is notbiologically or otherwise undesirable, i.e., the material may beadministered to an individual along with the selected therapeutic agentwithout causing any undesirable biological effects or interacting in adeleterious manner with any of the other components of thepharmaceutical composition in which it is contained. Similarly, a“pharmaceutically acceptable” salt or a “pharmaceutically acceptable”ester of a novel compound as provided herein is a salt or ester that isnot biologically or otherwise undesirable.

In describing the location of groups and substituents, the followingnumbering system will be employed to conform the numbering of thecyclopentanophenanthrene nucleus to the convention used by the IUPAC orChemical Abstracts Service:

The five- and six-membered rings of the steroid molecule are oftendesignated A, B, C, and D as shown. The term “steroid” as used herein isintended to mean compounds having the aforementionedcyclopentanophenanthrene nucleus.

In these structures, the use of bold and dashed lines to denoteparticular conformation of groups follows the IUPAC steroid-namingconvention. The symbols “α” and “β” indicate the specific stereochemicalconfiguration of a substituent at an asymmetric carbon atom in achemical structure as drawn. Thus “α,” denoted by a broken line,indicates that the group in question is below the general plane of themolecule as drawn, and “β,” denoted by a bold line, indicates that thegroup at the position in question is above the general plane of themolecule as drawn.

Synthetic Methods:

The synthetic methods of the invention all proceed from estrone-3-methylether via 21-hydroxy-19-norpregna-4-en-3-one as an intermediate. It willbe understood by those working in the field of steroid chemistry thatthe cyclopentanophenanthrene nucleus may be substituted with one or moresubstituents that do not interfere with the synthetic steps describedherein.

To prepare the substituted or unsubstituted21-hydroxy-19-norpregna-4-en-3-one intermediate, a substituted orunsubstituted estrone-3-methyl ether is first converted to a compoundhaving the structural formula (I) by reaction with a triethylphosphonoacetate or an analogous reagent (see Example 1).

(I)

In structural formula (I):

X is lower hydrocarbyl;

R¹ is hydrogen or CR¹¹R¹², wherein R¹¹ and R¹² are hydrogen or loweralkyl;

R² is selected from the group consisting of hydrogen, hydroxyl, alkyl,—OR¹³, and —SR¹³ wherein R¹³ is alkyl;

R⁴, R⁵, R⁶, and R⁷ are independently selected from the group consistingof hydrogen and lower alkyl;

R⁹ is hydrogen or hydrocarbyl; and

R¹⁰ is methyl or ethyl.

A preferred subset of the aforementioned compounds has the structure offormula (II)

wherein X is lower alkyl and R⁶ is hydrogen or lower alkyl.

For example, X may be ethyl, and R⁶ may be methyl (see compound 2 inFIGS. 2, 3, and 4).

In order to convert compound (I) to the substituted or unsubstituted21-hydroxy-19-norpregna-4-en-3-one intermediate (III)

compound (I) is treated with an alkali metal and ammonia or analkylamine using known reaction conditions appropriate for a Birchreduction; see, e.g., March et al., Advanced Organic Chemistry, FourthEdition (N.Y.: Wiley, 1992), section 5-10 and references cited therein.Suitable alkali metals include lithium, potassium and sodium, and thereaction preferably takes place in liquid ammonia and optionally in thepresence of an alcohol.

In compound (III):

R¹, R², R⁴, R⁵, R⁷, R⁹, and R¹⁰ are as defined for formula (I), R³ ishydrogen or hydrocarbyl, typically hydrogen or alkyl, preferablyhydrogen or lower alkyl such as methyl, and R¹⁹ is hydroxyl,hydroxymethyl (CH₂OH), protected hydroxyl, protected hydroxymethyl,activated hydroxyl, or activated hydroxymethyl. By “activated” is meantthat a hydroxyl group is modified so as to enable reaction with anincoming nucleophile; generally, this means that a hydroxyl group —OH isconverted to an —O-LG moiety wherein LG is a leaving group. Activationcan involve, for example, reaction with MsCl, TsCl, SOCl₂, SOBr₂, or thelike (“Ms” meaning mesyl and “Ts” meaning tosyl). By “protected” ismeant that the hydroxyl group will not undergo reaction in a particularstep, but by virtue of a protecting group Pr, the —O—Pr moiety remainsintact and can be treated, e.g., with base or acid, to regenerate theunprotected hydroxyl group following reaction. Suitablehydroxyl-protecting groups at the latter position include, but are notlimited to, Ms, Ts, acetyl (Ac), and tetrahydropyranyl (THP). It is tobe understood that the above-indicated activating and protectingmoieties may be used as either protecting groups or activating groupsdepending on the specific reaction condition.

Preferred intermediates encompassed by structural formula (III) have thestructure of formula (IV)

wherein:

R³ is hydrogen or lower alkyl; and

R¹⁹ is hydroxyl, hydroxymethyl, protected hydroxyl, or protectedhydroxymethyl.

In a representative and specific example of the foregoing reaction, amethod for synthesizing 21-hydroxy-19-norpregna-4-en-3-one is providedwhich comprises treating (IX)

wherein X and Y are independently lower alkyl, with an alkali metal inthe presence of ammonia or an alkylamine.

SR 16234 or its free base SR 16233 is synthesized from compound (III)using one of several methods, exemplified in the schemes of FIGS. 2, 3,4, 8, and 9. In the first three of these methods, when R¹⁹ is hydroxylor hydroxymethyl, preferably hydroxymethyl, the alcohol moiety isinitially converted to a leaving group displaceable with an incomingnucleophile as explained above. The remaining steps in the first threemethods then differ, as illustrated in FIGS. 2, 3, and 4. In the fourthmethod, as illustrated in the scheme of FIG. 8, the R¹⁹ alcohol moietyis initially converted to a protecting group, as explained above, a 7αgroups is attached to the B ring, the R¹⁹ protected group is unprotectedand then activated with a leaving group. The fifth method, illustratedin FIG. 9, first protects the R¹⁹ position and then proceeds asindicated.

In methods 1 and 2 (illustrated in FIGS. 2 and 3), a compound having thestructural formula (XII)

wherein m is zero or 1, and R¹, R², R⁴, R⁵, R⁷, and R¹⁰ are as definedabove, is initially provided. This compound is a subset of formula III.The —OH group at the 20- or 21-position (depending on whether m is zeroor 1, respectively) is then activated by conversion to an —O—LG moietywherein LG is a leaving group displaceable by nucleophilic attack, asexplained above; LG can be, for example, OMs, OTs, Cl, Br, etc.

At the same time that the —OH group at the 20- or 21-position isactivated, or subsequently, the following three reaction steps arecarried out: (1) the A ring of the steroid nucleus is oxidized(aromatized); (2) a 6-keto moiety is provided by exposure to gaseousoxygen in the presence of base (e.g., cesium carbonate or potassiumacetate); and (3) a protecting group is introduced at the 3-position soas to provide a protected hydroxyl group —OPr wherein Pr is theprotecting group. Suitable protecting groups include, but are notlimited to alkyl, lower alkyl, Ms, Ts, Ac, and THP.

Next, the leaving group LG is displaced with a hydroxyl-containingcompound having the structural formula (XIII)

wherein p is an integer in the range of 1 to 7 inclusive, R²¹ and R²²are lower alkyl or are linked together to form a five- or six-memberedheterocycloalkyl ring, and Q¹, Q², Q³, and Q⁴ are independently selectedfrom the group consisting of hydrogen, hydroxyl, carboxyl, alkoxy,alkyl, halogen, amino, and alkyl-substituted amino.

Prior, during, or subsequent to the aforementioned reactions,substitution at the 7-position is effected by reaction with an alkylhalide such as methyl iodide, in a suitable base such as lithiumdiisopropylamide, to provide a 7-lower alkyl, e.g., a 7-methyl,substituent. In method 1, illustrated in FIG. 2, alkylation at the7-position is conducted prior to attachment of the aromatic side chainat the 17-position, using an alkyl halide such as methyl iodide. Inmethod 2, illustrated in FIG. 3, alkylation at the 7-position isconducted after attachment of the aromatic side chain at the17-position, again using an alkyl halide such as methyl iodide. Inmethod 3, the 7-position is alkylated earlier, as implied above by thedefinition of R³ in structure (III). In either method 1 or 2, thecompound provided (exemplified as 6 in FIGS. 2 and 3) can be genericallyrepresented as (XVIII)

wherein R^(3A) represents the newly added lower alkyl group and theremaining substituents are as defined previously. It will be appreciatedthat other types of hydrocarbyl groups could be added at the 7-position,i.e., as R^(3A), by reaction with the appropriate hydrocarbyl halidereagents.

Compound (XVIII) is then reduced so as to remove the 6-keto andamidocarbonyl moieties using a standard reducing agent and conditions,e.g., lithium aluminum hydride (LAH) in the presence of aluminumchloride (AlCl₃), which also deprotects at the 3-position to result in afree hydroxyl group. The resulting compound thus has the structure (XI)

A representative compound of structure (XI) compound and key species is3-hydroxy-7α-methyl-21-[2′-methoxy-4′-(diethylaminomethyl)-phenoxy]-19-norpregna-1,3,5(10)triene(SR 16233) as illustrated in FIGS. 2 and 3. Compound (XI) may then beconverted to an acid addition salt by reaction with a suitable acidusing conventional procedures. For example, to convert the compound toSR 16234, the citrate salt of SR 16233, the reaction is conducted withcitric acid.

In method 3, illustrated in FIG. 4, the reaction steps followingsynthesis of compound (III) (exemplified as 3 in the figure) differ fromthe foregoing syntheses, as follows. Following protection of thehydroxyl or hydroxymethyl group at R¹⁹, the 7α-lower alkyl, e.g.,7α-methyl, group is synthesized by reaction with, for example, alkyllithium, e.g., methyl lithium, in the presence of lithium bromide (seeFIG. 4). The hydroxyl or hydroxymethyl group at R¹⁹ is then deprotectedby treatment with base (e.g., an inorganic hydroxide such as KOH orNaOH, in alcohol) using conventional means, followed by reaction with analdehyde that may be generically represented as (XIV)

a specific example of such an aldehyde, as illustrated in FIG. 4, isvanillin, i.e., 4-hydroxy-3-methoxybenzaldehyde. This results in anintermediate having the structural formula (XV)

Then, in order to provide the desired amine, (XV) is treated with analkylamine having the structure HNR²¹R²² under reaction conditionseffective to produce the amine (XVI)

While compound (XVI) is a valuable intermediate in the ultimatesynthesis of SR 16234 and analogs thereof, it has additional value as atherapeutic agent, particularly in the treatment of prostate disorderssuch as prostatic cancer. Preferred compounds within this group have thestructural formula (XVII)

wherein:

R^(3A) is alkyl, most preferably lower alkyl such as methyl;

m is zero or 1;

p is an integer in the range of 1 to 7 inclusive;

R²¹ and R²² are lower alkyl or are linked together to form a five- orsix-membered heterocycloalkyl ring; and

Q¹, Q², Q³, and Q⁴ are independently selected from the group consistingof hydrogen, hydroxyl, carboxyl, alkoxy, alkyl, halogen, amino, andalkyl-substituted amino.

In method 3, the A ring is then oxidized (aromatized) using, forexample, cuprous chloride in AcOH, or by using biological aromatization.SR 16233 results, which can be converted to SR 16234, as notedpreviously, by reaction with citric acid.

In method 4, as illustrated in FIG. 8, a compound having the structuralformula (XII) is used as the starting material. The —OH group at the 20-or 21-position (depending on whether m is zero or 1, respectively) isfirst protected by conversion to an —O—Pr moiety wherein Pr is aprotecting group, as explained above. Suitable protecting groupsinclude, but are not limited to alkyl, lower alkyl, Ms, Ts, Ac, and THP.As illustrated in FIG. 8, acetyl is a preferred protecting group forthis purpose, as the acetate moiety allows for easy and efficientpurification of the resultant acetate via recrystallization.

Next, a dienyl acetate having structural formula (XX) is formed byintroduction of a protecting group, Pr², at the 3-position.

In structural formula (XX), m, R¹, R², R⁴, R⁵, R⁷, and R¹⁰ are asdefined above, and Pr¹ and Pr² are the respective protecting groups onthe 20- or 21- and the 3-position and may be the same or different. Asdiscussed above, preferred protecting groups include, but are notlimited to, alkyl (particularly lower alkyl), acetyl, Ms, Ts, and THP.The 3-position protecting group, Pr², is then removed to form a dienonehaving structural formula (XXI)

wherein Pr¹, m, R¹, R², R⁴, R⁵, R⁷, and R¹⁰ are as defined above. Oncethe dienone has been synthesized, the compound is reacted with, forexample, a lower alkyl lithium, e.g., methyl lithium, in the presence oflithium bromide to form a 7α-alkylated compound having the structure(XXII)

wherein R^(3A) represents the newly added lower alkyl group and theremaining substituents are as defined above (see FIG. 8). The use ofacetate as the Pr¹ protecting group greatly facilitates the addition ofthe 7-alkyl group in the a position. While not wishing to be limited bytheory, it is believed that the acetate moiety forms a complex with thelithium and promotes introduction of the 7-alkyl functionality from thea face of the steroid.

The A ring of the 7α-alkyl steroid is then aromatized and the Pr¹protecting group removed using, for example, cuprous chloride in AcOH,biological aromatization, or the like.

The resulting diol will have structural formula (XIII)

wherein the various substituents are as defined above. The 3-positionand 20- or 21-position alcohol moieties of the diol are then protectedwith a suitable protecting group such as Ts, Ms, or the like. Asdiscussed above, Ms is a preferred protecting group. The protectedcompound is then treated with a hydroxyl-containing compound havingstructural formula (XIII), as discussed above with respect to method 1,resulting in a compound having the structure (XXIV)

wherein Pr represents the protecting group on the 3-position and theremaining substituents are as defined previously. This compound is thenreduced using a standard reducing agent and conditions, e.g., lithiumaluminum hydride (LAH), to reduce the amido moiety to an amine anddeprotect at the 3-position resulting in a free hydroxyl group. Theresulting compound thus has the structure (XI), which, as previouslydiscussed, may then be converted to an acid addition salt by reactionwith a suitable acid using conventional procedures.

In the last method, method 5, illustrated in FIG. 9, the 3-position of acompound having the structural formula (XII) is protected, the A ringaromatized and the desired 6-ketone introduced by the use of a catalyticamount of iodine in isopropanol while air is bubbled through thereaction mixture. This process results in a 6-ketone having thestructural formula (XXVI)

wherein Pr, m, R¹, R², R⁴, R⁵, R⁷, and R¹⁰ are as defined above. The 20-or 21-position hydroxyl group, depending on m, is then protected, e.g.,as a THP ether. Once the 20- or 21-position protecting group is inplace, substitution is effected at the 7-position by reaction with alower alkyl halide such as methyl iodide, in a suitable base such aslithium diisopropylamide, to provide a 7α-alkyl, e.g., a 7α-methyl,substituent and remove the 20- or 21-position protecting group. Afterthe 7α-alkyl group is in place, the 6-ketone is catalytically removedusing hydrogen and a platinum or palladium catalyst, e.g., 10% palladiumon carbon, and the 3-position is deprotected with a suitable reagent toprovide an alcohol, resulting in the diol having the structure (XXIII).The remainder of the method then proceeds as described for method 4.

Surprisingly, it has been discovered that a THP ether protecting groupwhen used in conjunction with an alkyl halide and a base, allows for ahighly stereoselective addition of a 7-alkyl group in the α position onstandard 6-keto steroid compounds. While not wishing to be limited bytheory, it is believed that the THP moiety sterically hinders additionof the 7-alkyl functionality from the β face of the steroid, therebypromoting introduction of the 7-alkyl functionality from the a face ofthe steroid. The use of a THP ether in the 7α-methylation of 6-ketoestradiol is described in Example 8.

Additional Intermediates:

Additional compounds within the scope of the invention are useful asintermediates in one or more of the foregoing syntheses and have thestructural formula (V)

wherein:

R¹ is hydrogen or CR¹¹R¹², wherein R¹¹ and R¹² are hydrogen or loweralkyl;

R² is selected from the group consisting of hydrogen, hydroxyl, alkyl,—OR¹³, and —SR¹³ wherein R¹³ is alkyl;

R³ is selected from the group consisting of hydrogen and hydrocarbyl,preferably hydrogen and alkyl, e.g., lower alkyl such as methyl;

R⁴, R⁵, and R⁷ are independently selected from the group consisting ofhydrogen and lower alkyl;

R^(6Mod) is selected from the group consisting of hydrogen, alkyl, acyl,—C(O)-aryl, and —C(O)-alkyl, hydroxyl-protecting groups, andhydroxyl-activating groups;

R^(8a) is selected from the group consisting of hydrogen, hydroxyl, oxo,and —OR¹⁸ wherein R¹⁸ is lower alkyl or lower acyl;

R⁹ is hydrogen or alkyl;

R¹⁰ is methyl or ethyl; and

R²⁰ is hydroxyl, hydroxymethyl, protected hydroxyl, protectedhydroxymethyl, activated hydroxyl, activated hydroxymethyl, or

in which m is zero or 1, p is an integer in the range of 1 to 7inclusive, and t is zero or 1, with the proviso that when R^(8a) is oxo,t is 1, and R²¹ and R²² are lower alkyl or are linked together to form afive- or six-membered heterocycloalkyl ring; and

Q¹, Q², Q³, and Q⁴ are independently selected from the group consistingof hydrogen, hydroxyl, carboxyl, alkoxy, alkyl, halogen, amino, andalkyl-substituted amino.

Preferred compounds within this group have the structure of formula (VI)

wherein:

R³ is hydrogen or lower alkyl;

R^(6Mod) is hydrogen or a hydroxyl-protecting group;

R^(8b) is hydrogen, hydroxy, or oxo; and

R¹⁹ is hydroxyl, hydroxymethyl, protected hydroxyl, or protectedhydroxymethyl. In particularly preferred compounds, R¹⁹ ishydroxylmethyl.

Other novel compounds useful as intermediates herein have the generalstructure (VII)

wherein:

R³ is hydrogen or hydrocarbyl, preferably hydrogen or alkyl, mostpreferably hydrogen or lower alkyl such as methyl;

R^(6Mod) is selected from the group consisting of hydrogen, alkyl, acyl,—C(O)-aryl, and —C(O)-alkyl, hydroxyl-protecting groups, andhydroxyl-activating groups;

R^(8b) is hydrogen, hydroxyl, or oxo, but preferably is hydrogen or oxo;

m is zero or 1;

p is an integer in the range of 1 to 7 inclusive;

t is zero or 1, with the proviso that when R^(8a) is hydrogen, t iszero, and when R^(8a) is oxo, t is 1;

R²¹ and R²² are lower alkyl or are linked together to form a five- orsix-membered heterocycloalkyl ring; and

Q¹, Q², Q³, and Q⁴ are independently selected from the group consistingof hydrogen, hydroxyl, carboxyl, alkoxy, alkyl, halogen, amino, andalkyl-substituted amino.

Still other compounds useful as intermediates herein have the generalstructure (VIII)

wherein R¹, R², R³, R⁴, R⁵, R¹⁰, and R¹⁹ are as defined previously.

Also useful are compounds having the structure (XXVII) and (XXVIII)

wherein R¹, R², R⁴, R⁵, R^(6Mod), R⁷, R¹⁰, and R¹⁹are as definedpreviously.Pharmaceutical Utility:

A number of those compounds identified herein as synthetic intermediatesalso find utility as pharmaceutical agents. For example, as alluded toin the preceding section, certain compounds useful as intermediates inthe synthetic methods described in the preceding section are also usefulin the treatment of prostate disorders, particularly prostatic cancer.

Prostatic cancer is the second most common malignancy in American men.Prostatic cancer may produce symptoms of urethral obstruction, either bydirect extension into the bladder or by spreading behind the bladderthrough-the seminal vesicles. Like-benign prostatic hyperplasia,prostatic cancer increases in prevalence with patient age, requiresandrogens for growth and development, and responds to antiandrogentreatment. Bostwick, et al., Cancer, 70(1 Suppl): 291-301 (1992).Prostatic cancer has been treated medically with some success throughsurgical techniques such as radical prostatectomy, and through radiationtherapy via either external beam or surgical implants of interstitialradioactive seeds into the prostate. Hormonal therapies availableinclude ablation by castration, administration of exogenous estrogens todeprive prostatic tumors of circulating androgens, releasing hormoneanalogues that inhibit testosterone synthesis, and/or administeringantiandrogens which block androgen action in the prostate itself.Chemotherapy has yielded discouraging results. See, e.g., Cecil Textbookof Medicine, 19th ed, 1353 (Wyngaarden et al., eds., W. B. Saunders1992).

Although a number of therapies have been proposed to treat each of thesedisorders, there remains a need in the art to provide a more effectivemethod of treating prostatic disorders such as prostatic cancer. It is,thus, a significant discovery that certain compounds of the inventionare useful in the treatment of prostatic cancer.

One group of compounds that may be used to treat prostatic cancer hasthe structural formula (XVI).

In compound (XVI), the various-substituents are as follows:

R¹ is CR¹¹R¹², wherein R¹¹ and R¹² are hydrogen or lower alkyl;

R² is selected from the group consisting of hydrogen, hydroxyl, alkyl,—OR¹³, and —SR¹³ wherein R¹³ is alkyl;

R^(3 is) hydrogen or hydrocarbyl, preferably hydrogen or alkyl, morepreferably hydrogen or lower alkyl such as methyl;

R⁴ and R⁵ are independently selected from the group consisting ofhydrogen and lower alkyl;

R⁷ is hydrogen or lower alkyl;

R¹⁰ is methyl or ethyl;

m is zero or 1;

p is an integer in the range of 1 to 7 inclusive;

R²¹ and R²² are lower alkyl or are linked together to form a five- orsix-membered heterocycloalkyl ring; and

Q¹, Q², Q³, and Q⁴ are independently selected from the group consistingof hydrogen, hydroxyl, carboxyl, alkoxy, alkyl, halogen, amino, andalkyl-substituted amino.

The compound may also be in the form of a pharmacologically acceptableacid addition salt.

Preferred compounds within the generic structure of formula (XVI) havethe structural formula (XVII)

wherein:

R³, m, p, R²¹, R²², Q¹, Q², Q³, and Q⁴ are as defined above for formula(XVI).

Two exemplary such compounds are as follows:

The compounds may be in the form of pharmacologically acceptable salts,prodrugs, or other derivatives or analogs, or they may be modified byappending one or more appropriate functionalities to enhance selectedbiological properties. Such modifications are known in the art andinclude those which increase biological penetration into a givenbiological system, increase oral bioavailability, increase solubility toallow administration by injection, and the like.

Acid addition salts of the free amine compounds can be prepared usingstandard procedures known to those skilled in the art of syntheticorganic chemistry and described, for example, by J. March, AdvancedOrganic Chemistry: Reactions, Mechanisms and Structure, 4th Ed. (N.Y.:Wiley-Interscience, 1992); conventional preparation of an acid additionsalt involves reaction of the free base with a suitable acid. Typically,the base form of the compound is dissolved in a polar organic solventsuch as methanol or ethanol and the acid is added at a temperature ofabout 0° C. to about 100° C., preferably at ambient temperature. Theresulting salt either precipitates or may be brought out of solution byaddition of a less polar solvent. Suitable acids for preparing acidaddition salts include both organic acids, e.g., acetic acid, propionicacid, glycolic acid, pyruvic acid, oxalic acid, malic acid, malonicacid, succinic acid, maleic acid, flumaric acid, tartaric acid, citricacid, benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid,ethanesulfonic acid,.p-toluenesulfonic acid, salicylic acid, and thelike, as well as inorganic acids, e.g., hydrochloric acid, hydrobromicacid, sulfuric acid, nitric acid, phosphoric acid, and the like. An acidaddition salt may be reconverted to the free base by treatment with asuitable base. Preferred acid addition salts of the present compoundsare the citrate, fumarate, succinate, benzoate, and malonate salts.

The therapeutic agents may be conveniently formulated intopharmaceutical compositions composed of one or more of the compounds inassociation with a pharmaceutically acceptable carrier. See Remington:The Science and Practice of Pharmacy, 19th Ed. (Easton, Pa.: MackPublishing Co., 1995), which discloses typical carriers and conventionalmethods of preparing pharmaceutical compositions which may be used asdescribed or modified to prepare pharmaceutical formulations containingthe compounds of the invention. The compounds may also be administeredin the form of pharmaceutically acceptable salts, or as pharmaceuticallyacceptable esters, as described in the preceding section.

The compounds may be administered orally, parenterally, transdermally,rectally, nasally, buccally, or via an implanted reservoir in dosageformulations containing conventional non-toxic pharmaceuticallyacceptable carriers, adjuvants, and vehicles. The term “parenteral” asused herein is intended to include subcutaneous, intravenous, andintramuscular injection. The amount of active compound administeredwill, of course, be dependent on the subject being treated, thesubject's weight, the manner of administration, and the judgment of theprescribing physician. Generally, however, dosage will be in the rangeof approximately 0.01 mg/kg/day to 10.0 mg/kg/day, more preferably inthe range of about 1.0 mg/kg/day to 5.0 mg/kg/day.

Depending on the intended mode of administration, the pharmaceuticalcompositions may be in the form of solid, semi-solid or liquid dosageforms, such as, for example, tablets, suppositories, pills, capsules,powders, liquids, suspensions, or the like, preferably in unit dosageform suitable for single administration of a precise dosage. Thecompositions will include, as noted above, an effective amount of theselected drug in combination with a pharmaceutically acceptable carrierand, in addition, may include other pharmaceutical agents, adjuvants,diluents, buffers, etc.

For solid compositions, conventional nontoxic solid carriers include,for example, pharmaceutical grades of mannitol, lactose, starch,magnesium stearate, sodium saccharin, talc, cellulose, glucose, sucrose,magnesium carbonate, and the like. Liquid pharmaceutically administrablecompositions can, for example, be prepared by dissolving, dispersing,etc., an active compound as described herein and optional pharmaceuticaladjuvants in an excipient, such as, for example, water, saline, aqueousdextrose, glycerol, ethanol, and the like, to thereby form a solution orsuspension. If desired, the pharmaceutical composition to beadministered may also contain minor amounts of nontoxic auxiliarysubstances such as wetting or emulsifying agents, pH buffering agentsand the like, for example, sodium acetate, sorbitan monolaurate,triethanolamine sodium acetate, triethanolamine oleate, etc. Actualmethods of preparing such dosage forms are known, or will be apparent,to those skilled in this art; for example, see Remington'sPharmaceutical Sciences, referenced above.

For oral administration, the composition will generally take the form ofa tablet or capsule, or may be an aqueous or nonaqueous solution,suspension, or syrup. Tablets and capsules are preferred oraladministration forms. Tablets and capsules for oral use will generallyinclude one or more commonly used carriers such as lactose andcornstarch. Lubricating agents, such as magnesium stearate, are alsotypically added. When liquid suspensions are used, the active agent iscombined with emulsifying and suspending agents. If desired, flavoring,coloring, and/or sweetening agents may be added as well. Other optionalcomponents for incorporation into an oral formulation herein include,but are not limited to, preservatives, suspending agents, thickeningagents, and the like.

Parenteral administration, if used, is generally characterized byinjection. Injectable formulations can be prepared in conventionalforms, either as liquid solutions or suspensions, solid forms suitablefor solution or suspension in liquid prior to injection, or asemulsions. Preferably, sterile injectable suspensions are formulatedaccording to techniques known in the art using suitable dispersing orwetting agents and suspending agents. The sterile injectable formulationmay also be a sterile injectable solution or a suspension in a nontoxicparenterally acceptable diluent or solvent. Among the acceptablevehicles and solvents that may be employed are water, Ringer's solution,and isotonic sodium chloride solution. In addition, sterile, fixed oilsare conventionally employed as a solvent or suspending medium.

The compounds of the invention may also be administered through the skinor mucosal tissue using conventional transdermal drug delivery systems,wherein the agent is contained within a laminated structure that servesas a drug delivery device to be affixed to the skin. In such astructure, the drug composition is contained in a layer, or “reservoir,”underlying an upper backing layer. The laminated structure may contain asingle reservoir, or it may contain multiple reservoirs. In oneembodiment, the reservoir comprises a polymeric matrix of apharmaceutically acceptable contact adhesive material that serves toaffix the system to the skin during drug delivery. Examples of suitableskin contact adhesive materials include, but are not limited to,polyethylenes, polysiloxanes, polyisobutylenes, polyacrylates,polyurethanes, and the like. Alternatively, the drug-containingreservoir and skin contact adhesive are present as separate and distinctlayers, with the adhesive underlying the reservoir which, in this case,may be either a polymeric matrix as described above, or it may be aliquid or hydrogel reservoir, or may take some other form.

Alternatively, the pharmaceutical compositions of the invention may beadministered in the form of suppositories for rectal administration.These can be prepared by mixing the agent with a suitable non-irritatingexcipient which is solid at room temperature but liquid at the rectaltemperature and therefore will melt in the rectum to release the drug.Such materials include cocoa butter, beeswax, and polyethylene glycols.

The pharmaceutical compositions of the invention may also beadministered by nasal aerosol or inhalation. Such compositions areprepared according to techniques well-known in the art of pharmaceuticalformulation and may be prepared as solutions in saline, employing benzylalcohol or other suitable preservatives, absorption promoters to enhancebioavailability, fluorocarbons, and/or other conventional solubilizingor dispersing agents.

Formulations for buccal administration include tablets,- lozenges,gels-and the like. Alternatively, buccal administration can be effectedusing a transmucosal delivery system.

It is to be understood that while the invention has been described inconjunction with the preferred specific embodiments thereof, theforegoing description as well as the examples that follow are intendedto illustrate and not limit the scope of the invention. Other aspects,advantages, and modifications within the scope of the invention will beapparent to those skilled in the art to which the invention pertains.

All patents, patent applications, and publications mentioned herein arehereby incorporated by reference in their entirety.

EXPERIMENTAL

The practice of the present invention will employ, unless otherwiseindicated, conventional techniques of synthetic organic chemistry,biological testing, and the like, which are within the skill of the art.Such techniques are explained fully in the literature. See, e.g., Fieseret al., Steroids (N.Y.: Reinhold, 1959), Djerassi, Steroid Reactions: AnOutline for Organic Chemists (San Francisco: Holden-Day, 1963), andFried et al., Organic Reactions in Steroid Chemistry vols. 1 and 2(N.Y.: Reinhold, 1972), for detailed information concerningsteroid-related synthetic procedures. Reference may be had toLittlefield et al., Endocrinology 127: 2757-2762 (1990) and Wakeling etal., Endocrinology 99: 447-453 (1983) for a description of thebiological testing procedures useful to evaluate compounds such as someof the therapeutic agents described and claimed herein.

In the following examples, efforts have been made to ensure accuracywith respect to numbers used (e.g., amounts, temperature, etc.) but someexperimental error and deviation should be accounted for. Unlessindicated otherwise, temperature is in degrees C and pressure is at ornear atmospheric. All solvents were purchased as HPLC grade, and allreactions were routinely conducted under an inert atmosphere of argonunless otherwise indicated. All reagents were obtained commerciallyunless otherwise indicated. Estrone 3-methyl ether was purchased fromBerlichem U.S.; ethamivan (vanillic acid diethylamide) was obtained fromFluka. NMR analyses were conducted on a Varian Gemini 300 and werereferenced to chloroform at δ 7.27. Mass spectra were recorded on an LKBModel 9000 combination gas chromatograph-mass spectrometer, interfacedwith a teknivent Vector-1 Data System.

The following examples are put forth so as to provide those of ordinaryskill in the art with a complete disclosure and description of how toprepare and use the compounds disclosed and claimed herein. Efforts havebeen made to ensure accuracy with respect to numbers (e.g., amounts,temperature, etc.) but some errors and deviations should be accountedfor.

EXAMPLE 1 Synthesis of 21-hydroxy-19-norpregna-4-en-3-one (3)

This example describes preparation of 21-hydroxy-19-norpregna-4-en-3-one(3) from estrone-3-methyl ether (1) as illustrated in the schemes ofFIGS. 2, 3, and 4.

Synthesis of (2): To a mixture of 28.4 g (0.1 mol) of estrone-3-methylether (1) and 90 g (0.4 mol) of triethyl phosphonoacetate in 175 mL ofTHF and 90 mL of ethanol, heated to reflux, was added 130 mL (0.4 mol)of a 21% solution of sodium ethoxide in ethanol. The mixture wasrefluxed overnight. The mixture was cooled and the volume reduced byhalf under vacuo. The mixture was poured into 2 L ice water withstirring. A gummy solid precipitated which was filtered, washed withwater and with stirring, and air-dried to give 2 as a solid. Yield 34 g(99%). The identity of the product was confirmed using ¹H NMRspectroscopy, and the NMR spectrum is shown in FIG. 10.

Synthesis of (3): To a three-necked flask equipped with a dry-icecondenser, overhead stirrer, argon gas inlet, and dropping funnel in adry-ice-acetone bath was added 1200 mL of liquid ammonia. To this −78°C. liquid was added 23.6 (3 mol) g of lithium in 1- to 3-inch pieces.After stirring 15 min, 350 mL of dry THF was slowly added to the bluesolution (containing lithium bronze). A solution of 30 g (84.6 mmol) of2 in 380 mL of t-butanol and 120 mL of THF was slowly added to the bluemixture. After stirring on the dry-ice-acetone bath, 2 g (0.25 moles)more of lithium was added. After stirring for 2 hrs, on thedry-ice-acetone bath, the blue color was mostly gone and a white-solidmixture remained. After three more hrs of stirring, 100 mL of methanolwas added and the stirred mixture was allowed to reach room temperatureand the ammonia evaporated with a flow of argon overnight. A solution of140 mL concentrated HCl, 350 mL of water and 500 mL of THF was slowlyadded to the white semi-solid mixture with overhead stirring. Moreconcentrated HCl was added until pH=1. The solution was stirred at roomtemperature for 3 hrs. The light yellow solution was poured into 1 L ofwater and extracted with 4× ethyl ether. The ether was washed with 500mL of saturated brine, dried over magnesium sulfate, filtered, andevaporated to dryness. Yield 27 g (100%) of a semi-solid crude product3. After silica gel column chromatography (0-20% ethyl acetate indichloromethane), 21.8 g (85%) of 3 as a white solid was isolated. Theidentity of the product was confirmed using ¹H NMR spectroscopy, and theNMR spectrum is shown in FIG. 11.

EXAMPLE 2 Synthesis of3-hydroxy-7α-methyl-21-[2′-methoxy-4′-(diethylaminomethyl)-phenoxy]-19-norpregna-1,3,5(10)trienecitrate (“SR 16234”) from 21-hydroxy-19-norpregna-4-en-3-one, method 1

SR 16234 was synthesized from 21-hydroxy-19-norpregna-4-en-3-one (3) asillustrated in FIG. 2, using the following procedure.

Synthesis of (4): To a solution of 1.32 g (4.36 mmol) of 3 (prepared inExample 1) in 30 mL of CH₂Cl₂ was added 2 mL of DHP (dihydropyran). Themixture was cooled to 0° C. and 40 mg (5%) of TsOH was added, and themixture was stirred for 1.5 h. Triethylamine (0.5 mL) was added to themixture and the mixture was filtered through a pad of silica gel(ether). The filtrate was concentrated to give 1.79 g of crude product,which was used right away without purification. To this crude productwas added 1.23 g (13.1 mmol) of phenol and 4.26 g (13.1 mmol) of CS₂CO₃followed by addition of 30 mL of sulfolane. The resulting mixture washeated at 125-130° C. under a stream of air for 6.5 hrs., and themixture was cooled to 65° C., and 10.7 mL of isopropyl bromide wasadded. The mixture was stirred for 2 hrs., and was cooled to ambienttemperature, diluted with ether and hexanes (80 mL/120 mL), washed withwater (50 mL×4), brine, dried, concentrated, and was chromatographed(10-15% EtOAc in hexanes) to give 735 mg (40%) of 4. The identity of theproduct was confirmed using ¹H NMR spectroscopy, and the NMR spectrum isshown in FIG. 12.

Synthesis of (5): To a solution of 210 mg (0.48 mmol) of 4 in 10 mL ofTHF was added 1 mL (2 mmol) of a 2.0 M solution of LDA (lithiumdiisopropylamide) in THF at 0° C. The mixture was stirred for 1 h,warmed to ambient temperature, and was treated with 1 mL of MeI. Theresulting mixture was refluxed for 30 min, and was cooled to 0° C.Methanol (10 mL) and TsOH (0.5 g) was added, and was stirred for 1.5 h.Triethylamine (1 mL) was added, and the mixture was concentrated, andwas chromatographed (30% EtOAc in hexanes) to give 70 mg (39%) of 5 asan oil. The identity of the product was confirmed using ¹H NMRspectroscopy, and the NMR spectrum is shown in FIG. 13.

Synthesis of (6): To a solution of 45 mg (0.12 mmol) of 5 and 1 mL ofEt₃N in 10 mL of CH₂Cl₂ was added 0.5 mL of methanesulfonic anhydride at0° C. The mixture was stirred for 20 min, and then filtered through apad of silica gel (ether). The filtrate was concentrated to give an oil,which was dissolved in 5 mL of DMF, and 67 mg (0.28 mmol) of vanillicacid diethylamide and 97 mg (0.30 mmol) of Cs₂CO₃ was added. Theresulting mixture was heated at 110° C. for 3 h, and was cooled anddiluted with ether (75 mL). The mixture was washed with water, brine,dried, concentrated, and was chromatographed (50% EtOAc in hexanes) togive 60 mg (85%) of 6. The identity of the product was confirmed using¹H NMR spectroscopy, and the NMR spectrum is shown in FIG. 14.

Synthesis of SR 16233: To a solution of 20 mg (0.03 mmol) of 6 in 5 mLof CH₂Cl₂ was added 10 mg (0.07 mmol) of AlCl₃ at 0° C. The mixture waswarmed to ambient temperature, stirred for 45 min, and filtered througha thin pad of silica gel (EtOAc). The filtrate was concentrated anddissolved in 10 mL of ether. This ether solution was added to a mixtureof AlCl₃ (120 mg, 0.9 mmol) and LiAlH₄ (1 mL of a 1 M solution in ether)in 5 mL of ether at ambient temperature. The mixture was stirredovernight and an aqueous solution of NaOH (15%) was added to the mixturedropwise until a white suspension was formed, and was filtered through apad of Celite. The filtrate was concentrated and chromatographed (5%-10%MeOH in CHCl₃) to give 6 mg (35%) of SR 16233. The identity of theproduct was confirmed using ¹H NMR spectroscopy, and the NMR spectrum isshown in FIG. 15. The mass spectrum is shown in FIG. 16.

Citrate salt of3-hydroxy-7α-methyl-21-[2′-methoxy-4′-(N,N-diethylamino-methyl)phenoxy]-pregna-1,3,5(10)-triene(SR 16234): The free base SR 16233 (240.5 g, 0.476 mol) was dissolved ina total volume of methanol (1.700 mL, ˜7 mL/g of base). To the hotsolution was added citric acid (93.5 g, 0.487 mol) (2% excess). Thecombined clear reaction mixture was stirred and crystallization startedand quickly proceeded. Finally, the reaction mixture was left overnight.The crystalline material was filtered off and then washed with a smallamount of cold methanol and ether. The crystalline material was driedunder vacuum to give 309.0 g or 93% product as an off-white powder, m.p.154-155 C. The ¹H NMR spectrum is shown in FIG. 17, and the massspectrum is shown in FIG. 18.

EXAMPLE 3 Synthesis of3-hydroxy-7α-methyl-21-[21-methoxy-4′-(diethylaminomethyl)-phenoxy]-19-norpregna-1,3,5(10)trienecitrate (“SR 16234”) from 21-hydroxy-19-norpregna-4-en-3-one, method 2

SR 16234 was synthesized from 21-hydroxy-19-norpregna-4-en-3-one (3) asillustrated in FIG. 3, using the following procedure.

Synthesis of (7): To a mixture of 1.512 g (5 mmol) of 3 (synthesized inExample 1) and 1.06 g (10.5 mmol) of Et₃N in 25 mL of sulfolane wasadded 1.03 g (9 mmol) of MsCl dropwise at ambient temperature, and thenstirred for 30 min. To this mixture was added 1.34 g (6 mmol) ofvanillic acid diethylamide and 1.96 g (6 mmol) of Cs₂CO₃. The resultingmixture was heated at 110-115° C. under a stream of air for 7 h, cooledto 85° C., and 2 mL of isopropyl bromide was added. The mixture wasstirred for 1 h, and was diluted with ether and CHCl₃ (100 mL/20 mL),washed with water and brine, dried with sodium sulfate, concentrated,and chromatographed (5% acetone in CH₂Cl₂) to give 804 mg (27%) of 7 asa yellow glass. The identity of the product was confirmned using ¹H NMRspectroscopy. The NMR spectrum is shown in FIG. 19.

Synthesis of (6): To a solution of 302 mg (0.54 mmol) of 7 in 12 mL ofTHF was added 0.67 mL (1.35 mmol) of a 2.0 M solution of LDA in THF at0° C. The mixture was stirred for 30 min, warmed to ambient temperature,and treated with 760 mg (5.4 mmol) of MeI. The resulting mixture wasrefluxed for 1.5 h, quenched into water, and extracted with ether (50mL). The organic layer was dried (sodium sulfate), concentrated, andchromatographed (15% EtOAc in CH₂Cl₂) to give 233 mg (75%) of 6 as anoil.

SR 16233 and SR 16234 were then synthesized from 6 as described inExample 2.

EXAMPLE 4 Synthesis of3-hydroxy-7α-methyl-21-[2′-methoxy-4′-(diethylaminomethyl)phenoxy-19-norpregna-1,3,5(10)trienecitrate (“SR 16234”) from 21-hydroxy-19-norpregna-4-en-3-one, method 3

SR 16234 was synthesized from 21-hydroxy-19-norpregna-4-en-3-one (3) asillustrated in FIG. 4, using the following procedure.

Synthesis of (8): To a suspension of alcohol 3 prepared in 84% yieldfrom estrone (12.1 g, 40 mmol) in isopropenylacetate (120 mL) was addedsilica gel containing 3% sulfuric acid (0.55 g). This reaction mixturewas heated at reflux for 4 h (after 2 h no change in TLC 30%EtOAc/hexane). The reaction mixture was filtered through a thin pad ofcelite/silica gel and the excess reagent was removed in vacuo. Theresidue became semisolid. The product was dried under high vacuum togive a crude yield (15.6 g or 100%). This compound was used in thesynthetic step without further purification. NMR was in accordance withthe proposed structure.

Synthesis of (9): Crude product 8 (˜40 mmol) was dissolved into acetone(100 mL), water (32 mL), acetic acid (12 mL), and pyridine (7 mL), andto this solution was added sodium acetate (22.8 g). This mixture wascooled in an ice/water bath and N-bromo succinimide (8.9 g or 50 mmol)was added (protected from light). The combined reaction mixture wasstirred at 0 to +5° C. for 3 h. TLC (20% EtOAc/hexane) showed nostarting material. The reaction mixture was poured into an ice cold sat.sodium chloride solution. This mixture was extracted 3 times with ether.The combined ether solution was washed with sat. sodium chloridesolution, dried over Na₂SO₄, and evaporated in vacuo to give the crudebrominated product. This product was dehydrobrominated in the followingway. The bromo compound was dissolved into DMF (72 mL). This solutionwas added to a hot suspension of lithium bromide (11.6 g) and lithiumcarbonate (11.6 g) in DMF (300 mL). The reaction mixture was heated atreflux for 1 h. The reaction mixture was cooled and filtered and theresidue was washed with some DMF. The filtrate and the washings werecombined and added to ice/water. The aqueous solution was extracted withether 3 times. The combined either solution was washed with sodiumbicarbonate solution 4% and water and dried over sodium sulfate andconcentrated to a syrup. The crude material was purified on a silica gelcolumn, eluted with 25% ethyl acetate/hexanes. Yield afterrecrystallization from ethyl acetate 8.4 g, 62% from the 21-alcohol 3.NMR and MS were in agreement with the proposed structure.

Synthesis of (10): To a stirred suspension of cuprous iodide (4.16 g, 22mmol) in dry ether (30 mL), was added a 1.5 M methyl lithium, lithiumbromide complex in ether (20.0 mL, 30 mmol). To this solution, cooled to0-5° C. was added the steroid acetate 9 (2.5 g, 7.3 mmol) dissolved intoether (30 mL) over a period of 10 min. Stirring was continued for anadditional 15 min and then the reaction mixture was quenched with asaturated ammonium chloride solution. The aqueous phase was separatedand extracted twice with ether. The combined organic phase was washedtwice with ammonium chloride solution and then water and dried overMgSO₄. Evaporation of the solvent gave the crude material as a gum.Treatment of the crude material with p-toluene sulfonic acid indichloromethane gave the target compound in a yield of 1.8 g, 69%. NMRand MS were in agreement with the proposed structure.

Synthesis of (11): To the acetate 10 (0.53 g, 1.48 mmol) dissolved intomethanol (20 mL) was added KOH (40 mg) and the reaction mixture wasstirred at room temperature for 2 h. TLC showed complete reaction. Thesolvent was removed under reduced pressure. Water was added to theresidue and the aqueous phase was extracted with ether 3 times. Thecombined ether phase was washed with saturated sodium chloride solution,dried over Na₂SO₄ and evaporated to give a gum (0.48 g). Addition ofsome ether induced crystallization. The crystals were collected to give0.32 g of off-white (yellowish) crystals. Total yield 0.48 g, 100%. NMRand MS were in agreement with the proposed structure; the ¹H NMRspectrum of the product is shown in FIG. 20.

Synthesis of (12): A mixture of the steroid alcohol 11 (0.30 g, 0.95mmol), vanillin (0.310 g, 2.04 mmol), and triphenylphosphine (0.53 g,2.04 mmol) was dissolved into THF (8 mL). To this solution was addeddropwise a solution of diethylazadicarboxylate (0.37 g, 2.1 mmol). Afterstirring for 2 h the reaction was complete. Most of the solvent wasevaporated and the total residue was chromatographed on a silica gelcolumn and was eluted with 25% ethyl acetate/hexane. The fractions thatcontained the target compound were combined and evaporated to give 0.366g of target compound. Yield 0.366 g, 85.5%. NMR and MS were in agreementwith the proposed structure; the ¹H NMR spectrum of the product is shownin FIG. 21.

Synthesis of (13): To a stirred solution of the aldehyde 12 (0.150 g,0.33 mmol) in dichloroethane (4 mL) was added diethylamine (0.68 mL,0.66 mmol). After 15 min of stirring (the solution became reddish)sodium-triacetoxy borohydride (0.097 g or 0.46 mmol) was added in twoportions. After stirring for 2 h the reaction was complete. The reactionmixture was diluted with some dichloromethane and was then poured intoan aqueous solution of sodium bicarbonate (4%). The organic phase wasseparated and the aqueous phase was extracted once more withdichloromethane. The combined organic phase was washed with sodiumbicarbonate solution and saturated sodium chloride solution was driedover Na₂SO₄. Evaporation of the solvent gave a syrup that was purifiedon a silica gel column and eluted with 5% methanol/dichloromethane. Thefractions that contained the target compound were evaporated to give0.113 g, 67% of pure target compound. NMR and MS were in agreement withthe proposed structure; the ¹H NMR spectrum of the product is shown inFIG. 22.

Synthesis of SR 16233: To a stirred solution of 13 (0.085 g) in glacialacetic acid (3 ml) was added CuCl₂ (0.085 g). The mixture was stirredand heated at 100-105° C. for 24 hours. The reaction mixture was cooledand poured into ice-cold water. The aqueous phase was extracted twicewith dichloromethane. The organic phase was washed with NaHCO₃ and waterand was dried over MgSO₄. Evaporation of the solvent gave the targetcompound, which was then recrystallized from ethanol. Identity of theproduct, SR 16233, was confirmed using ¹H NMR spectroscopy.

EXAMPLE 5 Synthesis of3-hydroxy-7α-methyl-21-[2′-methoxy-4′-(diethylaminomethyl)-phenoxy]-19-norpregna-1,3,5(10)trienecitrate (“SR 16234”) from 21-hydroxy-19-norpregna-4-en-3-one, method 4

SR 16234 was synthesized from crude 21-hydroxy-19-norpregna-4-en-3-one(3) as illustrated in FIG. 5, using the following procedure.

Synthesis of 21-Hydroxy-19-norpregna-4-en-3-one 21-acetate (34): Crudeproduct 3 prepared in Example 1 (18.0 g) was dissolved in pyridine (100mL), and to this solution was added acetate anhydride (25 mL). Thereaction was stirred at room temperature for 5 h and then poured intoice/water. The aqueous solution was extracted with ether twice. Thecombined ether extract was washed with water, ice-cold 4% hydrochloricacid solution, and water, and then dried over sodium sulfate andevaporated to give a semi-crystalline compound. This material waspurified by chromatography to give 14.0 g of 35 (86%). ¹H NMR (CDCl₃) δ0.66 (s, 3H), 2.04 (s, 3H), 4.06 (m, 2H), 5.83 (s, 1H).

Synthesis of 3,21-Dihydroxy-19-norpregna-3,5-dien-diacetate (8): To asuspension of 35 (12.1 g, 40 mmol) in isopropenylacetate (120 mL) wasadded silica gel containing 3% sulfuric acid (0.55 g). This reactionmixture was heated at reflux for 4 h, filtered through a thin pad ofCelite, and excess reagent removed to give a semisolid product. Theproduct was dried under high vacuum to give 15.6 g of crude product 8(100%). The product from this reaction was used in the next step for thepreparation of 21-hydroxy-19-norpregna-4,6-dien-3-on-21-acetate (37)without further purification. ¹H NMR (CDCl₃) was in accordance with theproposed structure.

Synthesis of 21-Hydroxy-19-norpregna-4,6-dien-3-on-21-acetate (9): Crudeproduct 8 (15.6 g, ˜40 mmol) was dissolved in a mixture of acetone (100mL), water (32 mL), acetic acid (12 mL), and pyridine (7 mL), and tothis solution was added sodium acetate (22.8 g). This mixture was cooledin an ice/water bath, and N-bromo-succinimide (8.9 g, 50 mmol) was added(protected from light). The combined reaction mixture was stirred at 0°to +5 C. for 3 h. The reaction mixture was poured into an ice-coldsaturated sodium chloride solution and then extracted 3 times with etherand the ether extracts combined. The combined ether extract was washedwith saturated sodium chloride solution, dried over Na₂SO₄, andevaporated under vacuum to give the crude brominated product. Thisproduct was dehydrobrominated as follows: the bromo compound wasdissolved in dimethyl formamide (DMF, 72 mL) and then added to a hotsuspension of lithium bromide (11.6 g) and lithium carbonate (11.6 g) inDMF (300 mL). The reaction mixture was heated at reflux for 1 h, thencooled and filtered. The residue was washed with DMF. The filtrate andthe washings were combined and added to ice/water. The aqueous solutionwas extracted with ether three times and the extracts combined. Thecombined ether solution was washed with 4% sodium bicarbonate solutionand water, dried over sodium sulfate, and concentrated to a syrup. Thecrude material was purified on a silica gel column eluting with 25%ethyl acetate/hexanes to yield, after recrystallization from ethylacetate, 9.2 g (68%) of 9 from 8. ¹H NMR (CDCl₃) δ 0.69 (s, 3H), 2.05(s, 3H), 4.08 (m, 2H), 5.78 (s, 1H), 6.20 (m, 2H). MS (DCI) m/z 343(M+H).

Synthesis of 21-Hydroxy-7α-methyl-19-norpregna-4-en-3-on-21-acetate(10): To a stirred suspension of cuprous iodide (1.14 g, 6 mmol) in dryether (25 mL) was added a 1.5 M (9.6 mmol) methyl lithium/lithiumbromide complex in 6.4 mL of ether. This solution was cooled to 0-5° C.,and then the acetate 9 (0.69 g, 2 mmol) dissolved in ether (40 mL) wasadded over a period of 10 min. Stirring was continued for an additional15 min, and then the reaction mixture was quenched with a saturatedammonium chloride solution. The aqueous phase was separated andextracted three times with ether. The combined organic phase was washedtwice with ammonium chloride solution and once with water, and thendried over MgSO₄. Evaporation of the solvent gave the crude material asa gum. Treatment of the crude material with p-toluenesulfonic acid indichloromethane gave 0.48 g (67%) of crude acetate 10. ¹H NMR (CDCl₃) δ0.67 (s, 3H), 0.78 (d, 3H), 2.05 (s, 3H), 4.06 (m, 2H), 5.83 (s, 1H). MS(DCI) m/z 359 (M+H).

Synthesis of 21-Hydroxy-7α-methyl-19-norpregna-1,3,5(10)-triene (35): Toa solution of 10 (0.400 g, 1.04 mmol) in 4.5 mL of acetic acid was addedcopper(II) chloride (0.400 g). This reaction mixture was heated at 10°C. for 2 h. After 1 h, the reaction mixture was cooled and poured intowater. The aqueous phase was extracted three times with ether. Thecombined ether phase was washed with water, sodium bicarbonate, andsodium chloride solution and then dried over sodium sulfate. Evaporationof the solvent gave the crude product in quantitative yield (somephenolic acetate seemed to be present). The crude material washydrolyzed with potassium hydroxide in a mixture of methanol/water.Extraction with dichloromethane and evaporation of the solvent gave 0.28g (85%) of purified material 35. ¹H NMR (CDCl₃) δ 0.59 (s, 3H), 0.78 (d,3H), 3.55 (m, 2H), 6.48 (d, 1H), 6.58 (q, 1H), 7.09 (d, 1H).

Synthesis of 3,21-Dihydroxy-19-norpregna-1,3,5(10)-triene-bis-mesylate(36): Alcohol 35 (0.945 g, 3 mmol) was dissolved in dichloromethane (15mL) and triethylamine (2.0 mL). This solution was cooled to 0-5° C.(ice/water bath), and methanesulfonyl chloride (0.90 g, 7.8 mmol) wasadded dropwise. The reaction mixture was stirred for 2 h at 0° C., thenpoured into ice/water. The dichloromethane was separated, and the waterphase was extracted once more with dichloromethane. The dichloromethanewas washed with water and then sodium chloride solution and dried oversodium sulfate. Evaporation of the solvent gave 1.34 g (95%) of 36 as aslightly sticky, white crystalline material. ¹H NMR was in agreementwith the proposed structure. The crude material was used without furtherpurification in the preparation of 37.

Synthesis of3-Hydroxy-7α-methyl-21-(2′-methoxy-4′-N,N-diethylamido)phenoxy-19-norpregna-1,3,5(10)-triene-3-mesylate(37): To a solution-of 36 (1.20 g, 2.55 mmol) in 20 mL of DMF was addedvanillic acid diethylamide (0.68 g, 3.06 mmol) and potassium carbonate(1.0 g, 3.06 mmol). The reaction mixture was heated at 90° C. for 2 h,then cooled to room temperature and poured into ice/water. Somecrystalline material appeared and was filtered off. The aqueous phasewas extracted with ether twice. The combined ether phase was washed withwater and sodium chloride solution. Evaporation of the solvent gave 1.39g (91%) of off-white material 37. ¹H NMR (CDCl₃) δ 0.68 (s, 3H), 0.86(d, 3H), 3.13 (s, 3H), 3.89 (s, 3H), 3.95 (m, 2H), 6.8-7.05 (aromatic,4H), 7.32 (d, 1H). MS (DCI) m/z 597 (M+H).

Synthesis of (SR 16233): A solution of crude 37 (0.500 g, 0.84 mmol) inether (15 mL) was added dropwise to a suspension of LAH (0.160 g) inether (10 mL). The reaction mixture was stirred overnight. The residuewas poured into CH₂Cl₂. The CH₂Cl₂ phase was washed with water and thensodium chloride and evaporated to give a crude material that waspurified by column chromatography to give 0.378 g (95%) of SR 16233.Identity of the product, SR 16233, was confirmed using ¹H NMRspectroscopy. MS (DCI) m/z 505 (M+H).

Synthesis of SR 16234: The free base SR 16233 (240.5 g, 0.476 mol) wasdissolved in methanol (total volume 1.700 mL, ˜7 mL/g of base). To thehot solution was added citric acid (93.5 g, 0.487 mol) (2% excess). Asthe clear reaction mixture was stirred, crystallization began andproceeded fast. Finally the reaction mixture was left overnight. Thecrystalline material was filtered off and washed with a small amount ofcold methanol and ether. The crystalline material was dried under vacuumto give 316 g of SR 16234 (95%).

EXAMPLE 6 Synthesis of3-hydroxy-7α-methyl-21-[2′-methoxy-4′-(diethylaminomethyl)-phenoxy]-19-norpregna-1,3,5(10)trienecitrate (“SR 16234”) from 21-hydroxy-19-norpregna-4-en-3-one, method 5

SR 16234 was synthesized from crude 21-hydroxy-19-norpregna-4-en-3-one(3) as illustrated in FIG. 9, using the following procedure.

Synthesis of (20): To a solution of 1.125 g (3.7 mmol) of crude product3 in 60 mL of isopropanol was added 0.188 g (0.7 mmol) of iodine. Theresulting mixture was refluxed under a stream of oxygen for 2 h, thencooled to room temperature. The mixture was diluted with ether (150 mL),washed with water and then brine, dried, and concentrated to give anoil. Chromatographic separation (40% EtOAc in hexanes) gave 0.814 g(61%) of 20. ¹H NMR (CDCl₃) δ 0.64 (s, 3H), 1.32 (d, 3H, J=1.9 Hz), 1.34(d, 3H, J=1.9 Hz), 2.77 (dd, 1H, J=16.8 Hz, 3.3 Hz), 3.68 (m, 2H), 4.61(m, 1H), 7.07 (dd, 1H, J=8.4 Hz, 3.0 Hz), 7.33 (d, 1H, J=8.4 Hz), 7.55(d, 1H, J=3.0 Hz).

Synthesis of (4): To a solution of 0.814 g (2.3 mmol) of 20 in 20 mL ofCH₂Cl₂ was added 5 mL of dihydropyran (DHP) and 0.05 g of pyridiump-toluenesulfonate. The mixture was stirred at room temperature for 2 h,and Et₃N (0.5 mL) was added. The mixture was diluted with ether (30 mL),washed with water and then brine, dried, and concentrated to give 1.01 g(100%) of (4), which was used in the next reaction without purification.¹H NMR (CDCl₃) δ 0.64 (s, 3H), 1.32 (d, 3H, J=1.9 Hz), 1.34 (d, 3H,J=1.9 Hz), 2.76 (dd, 1H, J=16.8 Hz, 3.3 Hz), 3.35-3.91 (m, 4H), 4.10 (m,2H), 7.07 (dd, 1H, J=8.4 Hz, 3.0 Hz), 7.33 (d, 1H, J=8.4 Hz), 7.55 (d,1H, J=3.0 Hz). MS (DCl) m/z 441 (M+H).

Synthesis of (5): To a solution of 0.660 g (1.5 mmol) of 4 in 25 mL ofTHF was added 2.25 mL (4.5 mmol) of a 2.0 M solution of lithiumdiisopropyl amide (LDA) in THF at 0° C. The mixture was stirred for 40min, warmed to room temperature, and treated with 1 mL of MeI. Theresulting mixture was refluxed for 40 min, then cooled to 0° C. Methanol(10 mL) and TsOH (1 g) were added, and the mixture was stirred for 2 h.The mixture was diluted with ether (50 mL), washed with saturated NaHCO₃and then brine, dried, concentrated, and chromatographed (25% EtOAc inhexanes) to give 0.447 g (80%) of (5). ¹H NMR (CDCl₃) δ 0.64 (s, 3H),1.11 (d, 3H, J=7.6 Hz), 1.32 (d, 3H, J=1.5 Hz), 1.34 (d, 3H, J=1.5 Hz),3.70 (m, 2H), 4.61 (m, 1H), 7.07 (dd, 1H, J=8.4 Hz, 3.0 Hz), 7.33 (d,1H, J=8.4 Hz), 7.55 (d, 1H, J=3.0 Hz).

Synthesis of (28): To a solution of 0.225 g (0.6 mmol) of 5 in 30 mL ofmethanol was added 0.050 g of 10% Pd/C. The mixture was hydrogenatedunder 3 atm. of H₂ for 22 h, then filtered through a thin pad of silicagel. The filtrate was concentrated and chromatographed (20% EtOAc inhexanes) to give 0.168 g (77%) of 28. ¹H NMR (CDCl₃) δ 0.64 (s, 3H),0.84 (d, 3H, J=7.1 Hz), 1.32 (d, 3H, J=1.9 Hz), 1.34 (d, 3H, J=1.9 Hz),3.69 (m, 2H), 4.61 (m, 1H), 6.61-6.73 (m, 2H), 7.21 (m, 1H).

Synthesis of (35): To a solution of 0.108 g (0.3 mmol) of 28 in 20 mL ofCH₂Cl₂ was added 0.120 g (0.9 mmol) of AlCl₃ at room temperature. Theresulting mixture was stirred for 2.5 h, then filtered through a thinpad of silica gel (with ether as eluent). The filtrate was concentratedto give 0.084 g (92%) of 35. ¹H NMR (CDCl₃) δ 0.64 (s, 3H), 0.84 (d, 3H,J=7.1 Hz)l, 3.69 (m, 2H), 6.60-6.72 (m, 2H), 7.22 (m, 1H).

Synthesis of (36): Alcohol 35 (0.945 g, 3 mmol) was dissolved indichloromethane (15 mL) and triethylamine (2.0 mL). This solution wascooled to 0-5° C. (ice/water bath), and methanesulfonyl chloride (0.90g, 7.8 mmol) was added dropwise. The reaction mixture was stirred for 2h at 0° C., then poured into ice/water. The dichloromethane wasseparated, and the water phase was extracted once more withdichloromethane. The dichloromethane was washed with water and thensodium chloride solution and dried over sodium sulfate. Evaporation ofthe solvent gave 1.34 g (95%) of 36 as a slightly sticky, whitecrystalline material. ¹H NMR was in agreement with the proposedstructure. The crude material was used without further purification inthe preparation of 37.

Synthesis of (37): To a solution of 36 (1.20 g, 2.55 mmol) in 20 mL ofDMF was added vanillic acid diethylamide (0.68 g, 3.06 mmol) andpotassium carbonate (1.0 g, 3.06 mmol). The reaction mixture was heatedat 90° C. for 2 h, then cooled to room temperature and poured intoice/water. Some crystalline material appeared and was filtered off. Theaqueous phase was extracted with ether twice. The combined ether phasewas washed with water and sodium chloride solution. Evaporation of thesolvent gave 1.39 g (91%) of off-white material 37. ¹H NMR (CDCl₃) δ0.68 (s, 3H), 0.86 (d, 3H), 3.13 (s, 3H), 3.89 (s, 3H), 3.95 (m, 2H),6.8-7.05 (aromatic, 4H), 7.32 (d, 1H). MS (DCI) m/z 597 (M+H).

Synthesis of SR 16233: A solution of crude 37 (0.500 g, 0.84 mmol) inether (15 mL) was added dropwise to a suspension of LAH (0.160 g) inether (10 mL). The reaction mixture was stirred overnight. The residuewas poured into CH₂Cl₂. The CH₂Cl₂ phase was washed with water and thensodium chloride and evaporated to give a crude material that waspurified by column chromatography to give 0.378 g (95%) of SR 16233.Identity of the product, SR 16233, was confirmed using ¹H NMRspectroscopy. MS (DCI) m/z 505 (M+H).

Synthesis of SR 16234: The free base SR 16233 (240.5 g, 0.476 mol) wasdissolved in methanol (total volume 1.700 mL, ˜7 mL/g of base). To thehot solution was added citric acid (93.5 g, 0.487 mol) (2% excess). Asthe clear reaction mixture was stirred, crystallization began andquickly proceeded. Finally the reaction mixture was left overnight. Thecrystalline material was filtered off and washed with a small amount ofcold methanol and ether. The crystalline material was dried under vacuumto give 316 g of SR 16234 (95%).

EXAMPLE 7

Biological Evaluation:

Compound SR 16312, having the structural formula

was synthesized as described in Example 4 without methylation at the7-position of the steroid nucleus. The compound was evaluated for itsinhibitory effect on androgen-independent human prostate cancer cells,DU145 cells and PC-3 cells, in a standard in vitro androgen-independenthuman prostate cancer assay.

DU145 and PC-3 human prostate cancer cell lines were obtained from theAmerican Type Culture Collection, Rockville, Md. Eagle's minimumessential medium, RPMI-1640 medium, fetal calf serum, nonessential aminoacids, and sodium pyruvate were purchased from Sigma, St. Louis, Mo.

PC-3 cells were maintained in RPMI-1640 medium supplemented with 10%fetal calf serum (FCS) and DU145 cells in Eagle's minimum essentialmedium (MEM) supplemented with 10% FCS. 1% nonessential amino acids, and1 mM pyruvate. All cells were cultured at 37° C. in a 5% CO₂/ 95% airatmosphere in 100% humidity. To initiate the growth inhibition assay,cells were seeded at 5000 cells per well in a 24-well plate in 500 μl ofthe appropriate medium for the individual cell line and cultured underthe same conditions described above. Cells were allowed to attach for 24hours, then test compound was added in 10 μl aliquots. The test compoundwas dissolved in DMSO first and diluted with medium. The final DMSOconcentration was kept at 0.1%. Control cultures received vehicle alone.The medium in each well was changed every other day, with fresh testcompound added. After 7 days of treatment, viable cells in each wellwere measured using the MTT assay as described in “CellularProliferation Assay,” in Protocols and Applications, 3^(rd) Edition(Promega Corporation).

To perform the MTT assay, on Day 9, medium from each well was removedand 100 μl of fresh medium was added, followed by 15 μl of tetrazoliumdye solution. The incubation was continued for 4 hours, and then 100 μlof solubilization/stop solution was delivered into each well. (Duringthe four-hour incubation, viable cells converted the tetrazoliumcomponent of the dye solution to formazan, which gives a blue color.)

The plate was kept at room temperature overnight and the blue colormeasured at 575 nm on an ELISA plate reader. Based on the opticaldensity of samples treated with the test compound and that of thecontrol, the inhibitory effect of SR 16312 was evaluated. The resultsare set forth in FIG. 21. As may be seen in the figure, the compoundresulted in virtually 100% inhibition at concentrations of 5 μM orhigher.

EXAMPLE 8 7-αmethylation of 6-ketoestradiol using a THP protecting group

The stereoselective methylation of a 6-keto steroid according to thefollowing scheme was accomplished as described below.

Synthesis of 3,17β-Dihydroxy-6-keto-estra-1,3,5(10)triene-3,17-ditetrahydropyranyl ether( 38). To a solution of 0.100 gm of6-ketoestraidol in 2.0 ml of dichloromethane was added 0.5 g ofdihydropyran and 0.04 gm. of TsOH. The reaction was stirred for 18 h atroom temperature under argon. The reaction was poured into 4% sodiumbicarbonate and extracted with additional dichloromethane. The organicfractions were combined and dried over magnesium sulfate and evaporatedto dryness to afford 0.157 gm (96% yield) of an oil 38. The reaction wasnot further purified and was used in the following reaction as is.

Synthesis of 3,17β-Dihydroxy-6-keto-7α-methyl-estra-1,3,5(10) triene (39). To a solution of 0.140 g of diTHP analog 38 in 5 mL of drytetrahydrofuran was added 0.47 mL of 2.0 M lithium diisopropylamide in2.0 mL of tetrahydrofuran at room temperature. The reaction was stirredfor 1.0 h. and then 0.25 mL of methyl iodide was added. The mixture wasrefluxed for 3.0 h., cooled to 0° C., and diluted with 5.0 mL ofmethanol. To this mixture was added 0.025 g of p-toluene sulfonic acid.The reaction mixture was stirred for an additional 2.0 h. Triethyl amine(1.0 ml) was then added and the reaction mixture evaporated at reducedpressure to yield 0.155 g of crude 39. The crude mixture was analyzed byNMR and showed only one isomer at C-7 as determined by the presence ofonly one doublet at 1.05 ppm. The crude product was diluted withchloroform and chromatographed on silica gel using 30%ethylacetate/hexane to afford pure 39 as an oil. ¹H NMR 7.36-7.0 (m, 3H,aromatic), 3.70 (t, 1H, 17-H) 1.05 (d, J=7.5 Hz., 7α-CH₃) 0.74 (s,18-CH₃)

Synthesis of 7α-Methylestradiol: Compound 39 may be converted into7α-methylestradiol using standard reaction conditions. For example, 10%Pd/C can be to a solution of 39 in methanol and then hydrogenated under3 atm. of H₂ for several hours. The hydrogenated product may then becollected by filtration through a thin pad of silica gel.

1. A compound having the structural formula (III)

wherein: R¹ is hydrogen or CR¹¹ R¹², wherein R¹¹ and R¹² are hydrogen orlower alkyl; R² is selected from the group consisting of hydrogen,hydroxyl, alkyl, —OR¹³, and —SR¹³ wherein R¹³ is alkyl; R³ is selectedfrom the group consisting of hydrogen and lower alkyl; R⁴, R⁵, and R⁷are independently hydrogen or lower alkyl; R⁹ is hydrogen; R¹⁰ is methylor ethyl; and R¹⁹ is hydroxyl, hydroxymethyl, protected hydroxyl,protected hydroxymethyl, activated hydroxyl, or activatedhydroxylmethyl.
 2. The compound of claim 1, having the structuralformula (IV)

wherein: R³ is hydrogen or lower alkyl; and R¹⁹ is hydroxyl,hydroxymethyl, —O-acetyl, or —O-tetrahydropyranyl.
 3. The compound ofclaim 2, wherein R³ is hydrogen or methyl, and R¹⁹ is hydroxymethyl. 4.The compound of claim 3, wherein R³ is hydrogen.
 5. The compound ofclaim 3, wherein R³ is methyl.
 6. The compound of claim 2, wherein R³ ishydrogen or methyl, and R¹⁹ is hydroxyl.
 7. The compound of claim 6,wherein R³ is hydrogen.
 8. The compound of claim 6, wherein R³ ismethyl.
 9. A method for synthesizing a compound, comprising treating astarting material having the structural formula (I)

with an alkali metal in the presence of ammonia or an alkylamine,wherein, in formula (I), X is lower alkyl; R¹ is CR¹¹R¹², wherein R¹¹and R¹² are hydrogen or lower alkyl; R² is selected from the groupconsisting of hydrogen, hydroxyl, alkyl, —OR¹³, and —SR¹³ wherein R¹³ isalkyl; R⁴, R⁵, R⁶, and R⁷ are independently selected from the groupconsisting of hydrogen and lower alkyl; R⁹ is hydrogen or hydrocarbyl;and R¹⁰ is methyl or ethyl, resulting in a reaction product having thestructural formula (VIII)


10. A method for synthesizing 21-hydroxy-19-norpregna-4-en-3-one,comprising treating (IX)

wherein X and Y are independently lower alkyl, with an alkali metal inthe presence of ammonia or an alkylamine.